An experimental study of the amides of aromatic carboxylic acids as radiosensitizing agents]

In experiments with mice a study was made of the radiosensitizing efficacy of 10 aromatic carbonic acid amides, benzene, naphthalene, pyridine and quinoline derivatives. It has been found, for this group of substances, that there is a direct correlation between the ability of the substance to reduce the splenic endocolonies production and the inhibitory activity with regard to poly(ADP-ribose) polymerase of thymocyte nuclei. Within the group of substances under study, new agents are found and described and new relationships are revealed between their chemical structure and biological activity.     

Substance 48/80 and experimental inflammation

Substance 48/80 (condensation product of p-methoxy-N-methylphenethylamine with formaldehyde) is known to cause release of histamine and serotonin from the granules in mastocytes. The effect of this substance on the course of experimental inflammation was studied in rats. It was found that substance 48/80 produced local reactions (paw oedema, pleural exudate), while after systemic administration it exerted an antiexudative and antioedematous effect. It is suggested that local signs after administration of the substance are caused, probably, by histamine and serotonin release from the mastocytes and participation of these substances in the inflammatory reaction, since this reaction was partly blocked by antihistamine and antiserotonin agents. The mechanism of inhibition of the inflammatory reactions after systemic administration of the substance is discussed.     

Variations in Endogenous Gibberellins in Developing Bean Seeds II. Changes Induced in Acidic and Neutral Fractions by GA(1)

Immature (8-mm), medium mature (11-mm), and mature green (16- and 17-mm) bean seeds (Phaseolus vulgaris L. cv. Kentucky Wonder and Bountiful) were incubated in gibberellin A₁ solutions for 24 hours at 20°. Extracts from the seeds were separated into nonacidic, acidic ethyl acetate, and acidic butanol fractions. These were chromatographed. The eluates of the chromatograms were tested on Progress No. 9 dwarf peas grown under red light. The level of neutral gibberellin-like substances remained unchanged in immature seed, but they increased markedly in mature green seeds. Coincident with increased levels of the neutral substances, there were significant decreases in acidic ethyl acetate-soluble gibberellin-like substances, including applied GA₁, and in 1 acidic butanol-soluble gibberellin-like substance. Seed incubation in GA₁ brought about increased activity of substance B-II in immature and medium mature seeds. The level of butanol-soluble gibberellin-like substance B-I in seeds of any size was not affected by incubation in GA₁. Considering the marked increases in activity induced in the neutral fraction and the decreases in activity of certain eluates from the chromatograms of the acidic fractions, it was concluded that the neutral fraction may serve as a reserve form of gibberellins in the dry seed. The acidic ethyl acetate substances and substance B-II may be required for normal development of the bean seed.     

Verification of a REACH Environmental Prioritization System Against Regulatory Risk Indices

A prioritization method that was developed to rank chemical substances on the basis of their environmental impact was applied to 230 new substance notifications from earlier European chemical legislation (67/548/EEC). The method encompasses three steps: (1) assigning an environmental hazard score, (2) assigning an environmental exposure score, and (3) combining these two scores into one priority score. In this study, the resulting scores ranged between 4 (highest priority) and 15 (lowest priority). The scores were compared with results from risk assessments available for 138 of the 230 substances. For most substances in these assessments, a priority score of 12 or higher was associated with no or limited risk, while a score of 11 or lower represented high risk or led to the conclusion that risk reduction measures were required. This categorization applied to all but 15 of the 138 substances. The method was also used for ranking the first 15 Substances of Very High Concern (SVHC) under REACH regulation, to compare the priority scores of new substances to those of the SVHC. In sum, the prioritization method seems to be valuable to identify substances of concern with respect to the environment.     

Chemical agents in neoplastic diseases; an evaluation of chemotherapeutic substances for clinical management

The rapid appearance of many new chemical substances which possess some antineoplastic effects has created a complex problem for the practicing physician. These agents which have shown promise in man and lower animals are grouped according to their modes of action. Each substance is discussed thoroughly with regard to its structure, activity, and influence upon the neoplasms of man. Key references are cited, and the practical value of each chemical agent is defined. The proper methods of administration of the compounds recommended for use are carefully described. In addition a section on agents whose therapeutic value has been disproven is also included.     

CHEMICAL AGENTS IN NEOPLASTIC DISEASES—An Evaluation of Chemotherapeutic Substances for Clinical Management

The rapid appearance of many new chemical substances which possess some antineoplastic effects has created a complex problem for the practicing physician. These agents which have shown promise in man and lower animals are grouped according to their modes of action. Each substance is discussed thoroughly with regard to its structure, activity, and influence upon the neoplasms of man. Key references are cited, and the practical value of each chemical agent is defined. The proper methods of administration of the compounds recommended for use are carefully described. In addition a section on agents whose therapeutic value has been disproven is also included.     

Water and oleyl alcohol as stationary liquid phases in gas—liquid chromatography : Determination of partition coefficients of volatile substances for analysis of quantitative structure—activity relationships

Indirect determination of partition coefficients of volatile substances in the system oleyl alcohol—water for analysis of quantitative structure—activity relationships is discussed. Water and oleyl alcohol were used as stationary liquid phases in gas—liquid chromatography. In order to correct the results for adsorption effects, two new procedures using a standard substance were suggested. The procedures were compared with a procedure used by Conder et al. Comparison of molar hydration enthalpies and entropies derived from experimental results of a series of aliphatic alcohols with calorimetric data proved that all procedures under consideration yielded true partition coefficients.     

Inhibitory effect of phospholipids on P-glycoprotein: Cellular studies in Caco-2, MDCKII mdr1 and MDCKII wildtype cells and P-gp ATPase activity measurements

Phospholipids are widely used excipients for pharmaceutical formulations, such as for preparing biphasic systems or to solubilize or encapsulate poorly soluble drugs. The present study investigates a new property of this class of substance: its ability to inhibit the efflux transporter Pglycoprotein (P-gp). P-gp is expressed in the intestinal epithelium, thereby significantly impairing the systemic absorption of various pharmaceutically active substances. The phospholipid screening performed in this study involved derivatives with different headgroups and fatty acid residues and a number of experimental parameters. For in vitro studies we carried out transport experiments and calcein accumulation assays in Caco-2- and MDCKII mdr1 and wildtype cell lines. The three compounds which displayed significant P-gp inhibition in both assays and in Caco-2 as well as in MDCKII mdr1, consisted of phosphatidylcholine (PC) and either two saturated fatty acid residues of eight (8:0 PC) or ten carbon atoms (10:0 PC), or of two unsaturated docosahexaeonic acid residues (cis-22:6 PC).Supported by P-gp ATPase activity measurements, 8:0 and 10:0 PC were assumed to function as direct P-gp inhibitors interacting with the transporter probably in their monomeric state, whereas a different, as yet unknown mechanism of action applied for cis-22:6 PC.Because of their proven ability to significantly inhibit P-gp in vitro, these phospholipids shall further be elucidated in vivo, whether they may truly serve to increase the bioavailability of orally applied drugs with a P-gp substrate character.     

Use of biophotonic imaging as a training aid for administration of substances in laboratory rodents

Dosing of experimental animals and the removal of blood are two of the most frequent procedures performed in biomedical research using live animals. Despite the apparently simple nature of these procedures, they can, if not correctly carried out, have significant effects on the welfare of the animals and the scientific value of the results. There are several methods by which research staff may obtain training in the administration of substances. These include practical demonstrations during teaching courses; observation of techniques; videos and educational computer programs and practising on recently killed animal cadavers or plastic animal models. Each method has its own advantages and disadvantages. A common factor encountered during training is the difficulty in assessing competency. This paper reports a pilot study on the use of bioluminescent imaging technology to assess competency in the administration of substances to rodents. Bioluminescence was rapidly detected after dosing of animals with a bioluminescent substance. However, living animals were required for a signal to be generated. The data presented suggest that this technology is ideal for use as a teaching aid and may also prove valuable in assessing the effectiveness of 'complex' and novel administration routes in 'realtime'.     

Analysis of acute and chronic effects of antidepressive agents in a learned helplessness model in mice

In experimental learned helplessness in mice determined by preliminary inavoidable aversive exposure, activity of tricyclic antidepressants (desipramine, chlorimipramine, amitryptyline), type A MAO inhibitors (pyrazidol), and atypical (zimelidine, trazodon, befuralin) antidepressants as well as that of potential antidepressants (LIS-30, DZK-153) were determined upon chronic administration. The tricyclic compounds, befuralin and DZK-153 removed learned helplessness only after 14 days of administration. The substances with a predominant serotoninomimetic action (zimelidin, trazodon in high doses, pyrazidol, LIS-30) showed high efficacy following 6 days of administration. Single administration of the substances under study did not make it possible to disclose their specific antidepressant activity.     

Modulation of the mitotic activity and population of the mast cells in the oral mucosa by substance P

To assess the effect of substances inducing mast cell degranulation (substance P and granuliberin R) on the mitotic indices of the gingiva stratified epithelium, basal cells from rats were studied in vivo. Seventy Lewis male rats were used in the study. The rats received injections of either 0.1 ml 0.9% NaCl (l0 rats), or substance P (10(-4), l0(-6), 10(-8) g/ml) (30 rats), or granuliberin R (10(-4), l0(-6), 10(-8) g/ml) (30 rats) into their mandibular gingiva in the vicinity of the right mental foramen. The mitotic index of keratinocytes was established after the kolchicine arrest (2 hours prior to material collection i.p. injection). The number of cells in metaphase was counted on 1000 consecutive basal layer cells after hematoxilin and eosin section staining. Mast cells were revealed using pinocyanol erythrosinate according to Bensley. Numerical density and morphometric features were analyzed. Substance P and granuliberin R injected into the gingiva affect the mast cells and the basal cell proliferation of the gingival epithelium. The diminished mitotic activity of basal layer cells was accompanied by degranulation and/or migration of mast cells under the basal membrane of the epithelium. After administration of high doses of granuloliberin R, mast cells were found in the deep connective tissue alligned towards the epithelium. A neuromediator from the trigeminal nerve (substance P) and substances from mast cells actively interfere in the proliferation of oral keratinocytes and the activity of connective tissue cells.     

PHOTOOXIDATIVE CONSUMPTION AND PHOTOREDUCTIVE FORMATION OF ASCORBIC ACID IN GREEN LEAVES

1. From leaves of barley and spinach, cellular components wereisolated and brought together under various conditions to investigatethe fate of ascorbic acid as affected by the components in thelight and dark. 2. A new colorimetric method for assaying ascorbic acid andsome other reducing substances was devised, measuring the colorof molybdenum-blue developed by the substances in the presenceof excess amounts of phosphomolybdate and inorganic acid. 3. The photooxidation of ascorbic acid by green and yellow filtrates,prepared from green and etiolated leaves of barley, was studiedby the ordinary as well as the new colorimetric method. In thepresence of oxygen, the oxidation of ascorbic acid was foundto be accelerated by light in the green filtrate, but not inthe yellow filtrate. 4. The oxidation of the endogenous reducing substance containedin the supernatant fraction of spinach leaf extracts was studiedin the presence of washed chloroplasts (spinach). In the presenceof oxygen, the rate of oxidation in the light was markedly higherthan in the dark. From the changes in absorption spectrum accompanyingthe reaction, the endogenous reducing substance in questionwas identified as ascorbic acid. 5. The occurrence of an endogenous precursor of ascorbic acidin spinach leaf extracts was disclosed. The photoreduction ofthis precursor into ascorbic acid was studied in the precenceof spinach chloroplasts. A specific inhibition of this reactionby phosphoglycerate and glycerophosphate was discovered. 6. The experimental results obtained were discussed in connectionwith the role of ascorbic acid in photosynthesis. (Received September 13, 1960; )     

Theoretical and applied aspects of experimental teratology]

The dependence of teratogenic effect from the agent specific properties, dose and exposition and the genotype of embryo and maternal organism is considered. The stage specificity of teratogens and the concepts of critical developmental periods are analyzed. The data on general mechanisms of embryonic defects related to the mutations and their phenocopies induced by teratogens are evaluated. The applied aspects of experimental teratology and, in particular, the testing of drugs' teratogenicity and the development of mathodical bases for the establishment of teratogens among the chemical pollutions are intimately connected with and depend on more profound studies of the theoretical bases of teratology. A new method of testing the chemical substances is proposed: search for embryotoxic and teratogenic factors in the blood of animals which were in contact with teratogens. With this aim the cleaving postimplantation mouse and rat embryos are cultivated in the medium with the blood serum from the animals treated with teratogens. This allows to detect in the blood not only the substance in question, but also the toxic products of its metabolism and the toxic substances formed in the maternal organism under the effect of this teratogen. The approaches to the express methods of estimation of teratogenicity are evaluated and the grounds of many steps testing the chemical polutions for teratogenicity are provided.     

Structural basis of neurohormonal control of gastric secretory activity

Distances between neural, endocrinal and working cells in the gastric wall tissue do not exceed some hundreds nm, i. e. they are within limits of the physiological parameters for the effect of biologically active substances diffusely spreading along the interstitium. A structural scheme of the neurohormonal regulatory mechanism is suggested, basing on the author's data and those of the literature. Combination of producer-mediator-cells and target-cells united by the interstitial gap, along which biologically active substances are transported, serves as its base. Mast cells--mobile endocrinic glands--and neural terminals of various modality may serve as a source for changing the modulatory tonus in the given tissue area. The cells producing mediators (neural and endocrine) are, in their turn, target-cells for other biologically active substances getting into the interstitium. The whole structure can be compared with the synaptic system, where the membranes of the producer-mediator-cells serve as the presynaptic pole, while the membranes of the target-cells play the role of the postsynaptic pole. The interstitial gap performes the part of the synaptic gap. In this peculiar diffuse synapse, the membranes of neural and endocrine cells serve as pre- and postsynaptic membranes simultaneously.     

Development of the protonema and bud formation in mosses

In the course of their development the protonemata of Funaria hygrometrica produce two different substances which diffuse into the substrate. In the chloronema a thermo-labile growth-promoting substance is formed. In the caulonema, after about 10 days, a substance is produced which is thermostable and soluble in amyl alcohol, which can be dialysed, and which functions as a growth inhibitor. Both substances also influence bud formation. This is at an optimum only when there is a certain balance between these two substances.
This promotion is fundamentally different from that brought about by treatment with kinetin, because kinetin can function only as an additional factor in promoting bud formation. Very probably it acts as an agent which creates centres of attraction toward which morphogenetic substances are drawn. This assumption is supported by the fact that kinetin cannot be transported and therefore has no 'after-effect'. It probably functions only in the caulonema cell it penetrates. It converts every caulonema cell into a 'reaction cell'.     

Novel selective melanocortin 4 receptor antagonist induces food intake after peripheral administration

We synthesized a new series of small cyclic melanocyte-stimulating hormone (MSH) analogues and screened them for binding affinity at the four MSH binding melanocortin (MC) receptors. We identified a novel substance HS131, with about 20-fold higher affinity for the MC4 receptor than the MC3 receptor. This substance proved to be antagonist for all the four MC receptors in a cAMP assay. HS131 is a six amino acid long peptide, has a molecular weight below 1000, and has only two amino acids in common with the natural MSH peptides. HS131 potently and dose dependently increased food intake after i.c.v. administration. Moreover, s.c. administration of HS131 (1.0 mg/kg) increased food intake, suggesting that HS131 may be able to pass the blood brain barrier. This cyclic low molecular weight peptidomimetic will enable studies of the functional role of the MC4 receptors by peripheral administration and it may be used as a template for further development of low molecular weight substances for the MC receptors.     

A critical evaluation of the 2011 ECHA reports on compliance with the REACH and CLP regulations and on the use of alternatives to testing on animals for compliance with the REACH regulation

On 30 June 2011, the European Chemicals Agency published two reports, one on the functioning of the REACH system, the other on the use of alternatives to animal testing in compliance with that system. The data presented are based on information gained during the first registration period under the REACH system, which included high production volume chemicals and substances of very high concern, which have the most extensive information requirements. A total of 25,460 registration dossiers were received, covering 3,400 existing, so-called 'phase-in', substances, and 900 new, so-called 'non-phase-in', substances. Data sharing and the joint submission of data are reported to have worked successfully. In the registration dossiers for these substances, results from new animal tests were included for less than 1% of all the endpoints; testing proposals (required for 'higher-tier' information requirements) were submitted for 711 in vivo tests involving vertebrate animals. The registrants mainly used old, existing experimental data, or options for the adaptation (waiving) of information requirements, before collecting new information. For predicting substance toxicity, 'read-across' was the second most-used approach, followed by 'weight-of-evidence'. In vitro toxicity tests played a minor role, and were only used when the respective test methods had gained the status of regulatory acceptance. All in all, a successful start to the REACH programme was reported, particularly since, in contrast to most predictions, it did not contribute to a significant increase in toxicity testing in animals.     

Study of United Kingdom product licence applications containing new active substances, 1987-9.

OBJECTIVES--To investigate the fate of product licence applications containing new active substances in relation to their degree of innovation and therapeutic category. To assess the numbers of volunteers and patients exposed to a new active substance when marketing autorisation is first sought. DESIGN AND SETTING--Observational study of records for each licence application submitted to the United Kingdom licensing authority for marketing authorisation from 1987 to 1989. SUBJECTS--118 product licence applications containing one or more new active substances. MAIN OUTCOME MEASURES--Success of application for product licence as assessed by the decision of the Committee on Safety of Medicines to advise the granting of a licence (with or without conditions) or provisionally advise its refusal on the grounds of quality, safety, or efficacy. Assessment of numbers of volunteers and patients exposed to each substance during premarketing studies and clinical trials, and the numbers of treated patients available for an assessment of safety. RESULTS--118 relevant product licence applications were submitted during the review. Although 60% (52/86) of semi-innovative products fell into one of three therapeutic categories (cardiovascular, central nervous system, or anti-infective agents), only 41% (13/32) of fully innovative products fell into these categories. 47 applications were granted (conditionally or unconditionally) but the success rate for fully innovative products (56%, 18/32) was greater than that for semi-innovative products (34%, 29/86). The number of volunteers and patients exposed to a new product at submission varied widely and tended to be greater for successful applications. CONCLUSION--The results suggest a broadening of the pharmaceutical industry''s research and development programmes and that a more liberal licensing policy exists for fully innovative products than for semi-innovative products. The relatively limited exposure of patients to new active substances at licensing underlines the importance of rigorous postmarketing surveillance.     

A new theory of infarction-genesis in cats

It can be shown that a number of substances that are derived from incubation have a good blocking capacity in myocardial infarction. There exists also a natural substance (intrinsic factor, i.f.) which can also block infarction. The same substances also inhibit arrhythmias of ischaemic origin. Thus a common root for myocardial infarction and arrhythmias could be inferred. A new dynamic method (T/2 velocity) was elaborated for evaluating anti-infarction drugs instead of using static T/2 values. Oxidation of i.f. in vitro and in vivo enhances the blocking capacity of artificial drugs reagented previously each other. The natural substance (i.f.) lost its blocking capacity after oxygenation, thus may be unable to compete with the above mentioned artificial substances. Ligation of the coronaries i.e. its myocardial infarction producing effect can also be inhibited by the same substances. No matter how infarction is produced, the same substances can block it. Since after cutting the vagi KCl elicits the same phenomena their reflex origin can be excluded.